Rotor blade arrangements of this kind are known in various configurations in the prior art and serve to convert the flow energy of a working fluid into rotational energy. A turbomachine such as a steam turbine or a gas turbine comprises a turbine casing and a turbine shaft which passes through the turbine casing and is connected to the drive shaft of a work machine, for example a generator. One or more rotor blade arrangements are held rotationally fixed on the turbine shaft, blades being held on each of these rotor blade arrangements in the form of a blade ring. During operation of the turbomachine, a circumferential force exerted by the working fluid, for example steam or hot gas, on the blades turns the turbine shaft, thus driving the work machine.
When assembling a rotor blade arrangement for a turbomachine, a blade carrier is provided with a circumferential blade ring. In that context, blades and spacers are inserted in alternation into a T-shaped slot running around the outer circumferential face of the blade carrier, and are shifted in the circumferential direction therein. To that end, the blades and spacers must be able to be shifted in the circumferential T-shaped slot. This is achieved by producing the blade roots and spacers with a clearance, in particular a radial clearance, with respect to the circumferential T-shaped slot. When assembling the blade ring on the blade carrier, the spacers and blade roots must be preloaded radially outward in order to minimize gaps that form between the spacers, the blade roots and the T-shaped slot, to ensure a secure fit in particular of the blades even at low rotational speeds of the turbine shaft and, where necessary, to be able to subsequently work the tips of the blades with a high degree of precision even in the mounted state.
For that reason, EP 2 562 356 A1 for example proposes inserting into the T-shaped slot support elements that are braced between the bottom of the T-shaped slot on the one hand and the undersides of the blades and the spacers on the other hand and press the blades and the spacers radially outward against shoulder faces of the T-shaped slot, and thus secure the blades and spacers in the radial direction. However, when assembling a rotor blade arrangement it must be ensured that the support elements remain at their intended position at the bottom of the T-shaped slot. This can be done for example by means of additional slots within the T-shaped slot, in which the support elements are held. Alternatively, as proposed in EP 2 562 356 A1, the support elements can also be dimensioned and configured such that they reciprocally hold themselves in position, at least in the circumferential direction. In order to compensate for any manufacturing tolerances, the support elements are produced with a certain excess length in the circumferential direction, so that the last support element that is to be inserted into the T-shaped slot must be appropriately shortened in order to fit in the remaining gap, which incurs an additional cost. A fundamental difficulty in handling such support elements lies in the fact that access to the intermediate space between the undersides of the spacers and blades on the one hand and the bottom of the T-shaped slot on the other, for the purpose of positioning the support elements therein, is extremely difficult.